1. Field of the Invention
Embodiments of the present invention generally relate to a method and apparatus for image and video coding using hierarchical sample adaptive band offset.
2. Description of the Related Art
Sample adaptive offset (SAO) was introduced for the next generation video coding standard called high efficiency video coding (HEVC). FIG. 1 is an embodiment depicting a block diagram for decoding Architecture of high efficiency video coding with adaptive loop filtering (ALF) and sample adaptive offset. As shown in FIG. 1, SAO is applied after deblocking filtering process, usually, before adaptive loop filtering (ALF).
SAO involves adding an offset directly to the reconstructed pixel from the video decoder loop in FIG. 1. The offset value applied to each pixel depends on the local characteristics surrounding that pixel. There are two kinds of offsets, namely band offset (BO) and edge offset (EO). BO classifies pixels by intensity interval of the reconstructed pixel, while EO classifies pixels based on edge direction and structure. In certain cases, the number of pixels increases but the number of bands stays the same. As a result, the system becomes less efficient.
Therefore, there is a need for an improved method and/or apparatus for a more efficient image and video coding using hierarchical sample adaptive band offset.